Daisy0138: The 1090 ES system is not half a system, it is a complete system. 978 is another system.
To my knowledge nowhere else in the world to the USA has used 978.
I'm not saying it's a good or bad idea not to use it. Rather I suspect there isn't the enough need compared to the USA to justify installation of 978.
Just like we don't have the equivalent of Nexrad weather available, there isn't the critical mass to warrant the development of a similar system for this part of the world. Someone has to pay for it and I suspect the cost would be more than users will be prepared pay.
If you feel so motivated you could provide a service like Nexrad, it doesn't have to be provided by the likes of ASA. Note Nexrad isn't provided by the FAA.